As the number and use of cordless devices grows, so does the possibility that communications involving separate devices will interfere with one another. The present invention is aimed at reducing the possibility that cordless devices might interfere with each others"" communications.
A typical cordless telephone system is made up of a base unit and handset. During the time when no telephone calls are being sent or received by the system, the base is typically scanning the frequency/channel environment surrounding the system. It does this to determine the clearest channel of communications between the base and handset. When a call is received or sent, the base unit seizes a pre-established channel which may or may not be a clear channel. As soon as a communications link is established the base commands the handset to change to a new channel.
The new channel has been previously xe2x80x9crankedxe2x80x9d or xe2x80x9corderedxe2x80x9d by the base as the best or clearest channel available prior to maintaining communications with the handset. Many cordless devices available today use the same ranking algorithms, e.g. received signal strength indication (xe2x80x9cRSSIxe2x80x9d), to determine which of the available channels is the clearest.
If two or more base units are operating within the same environment interference problems may arise if both base units need to initiate communications. For example, because both base units will be scanning the same radio frequency environment using the same ranking algorithm to determine the best channel available, each will probably try to seize the same channel. If this happens and the bases transfer communications over the same channel to different handsets, interference may occur.
Accordingly, it is an object of the present invention to provide cordless devices, programmed devices and methods which reduce the possibility that interference will occur in such an environment.
It is another object of the present invention to provide cordless devices, programmed devices and methods which order narrow band, communication channels to reduce the possibility that interference and like problems will occur in such an environment.
It is yet another object of the present invention to provide cordless devices, programmed devices and methods which order narrow band, communication channels using algorithms which are not based on channel clarity to reduce the possibility that interference and like problems will occur in such an environment.
Other objectives, features and advantages of the present invention will become apparent to those skilled in the art from the following description taken in conjunction with the accompanying drawings.
The present invention overcomes the problems associated with interference and the like by utilizing algorithms which order the available channels in a given environment by some additional criteria other than channel clarity/quality. By using criteria in addition to channel clarity, the devices and methods envisioned by the present invention create unique channel orderings not utilized by existing cordless devices. Thus, in an environment which requires or involves the use of multiple cordless devices, a device which comprises features of the present invention will select a channel of communication which is less likely to suffer from interference problems or the like.
In accordance with the present invention there are provided cordless devices, programmed devices and methods which provide the advantages just discussed.
The present invention provides for devices which order narrow band, communication channels. These devices comprise: a scanning unit or scanning means for scanning narrow band communication channels; and a ranking unit or ranking means for grouping the scanned channels into channel groups, each group comprising a channel or channels which has a channel clarity within a certain range and for ordering each group of channels using an algorithm which does not rely upon channel clarity. The ranking unit may be adapted to randomly select the xe2x80x9cnon-channel-clarity algorithmxe2x80x9d from a number of non-channel-clarity algorithms or select the algorithm by other means. Other preferred devices may additionally comprise an algorithm memory or memory means for storing non-channel-clarity algorithms and/or a ranking memory or memory means for storing ranked and/or ordered groups of channels.
In accordance with other aspects of the present invention there are provided methods which order narrow band, communication channels for a communications device. These methods comprise: scanning narrow band communication channels; grouping the scanned channels into channel groups, each group comprising a channel or channels which has a channel clarity within a certain range; and ordering each group of channels using a non-channel-clarity channel-clarity algorithms and/or storing ranked and/or ordered groups of channels. Other methods comprise selecting the non-channel-clarity algorithm from a number of non-channel-clarity algorithms and/or randomly selecting the non-channel-clarity algorithm from a number of non-channel-clarity algorithms.
The present invention further provides for programmed devices which order narrow band, communication channels. These programmed devices comprise programs or program means which in turn comprise program code or code means. In one embodiment, the program means comprises: program code means for scanning narrow band communication channels; program code means for grouping the scanned channels into channel groups, each group comprising a channel or channels which has a channel clarity within a certain range; and program code means for ordering each group of channels using a non-channel-clarity algorithm. Additional embodiments may comprise program code means for storing the ranked and/or ordered groups of channels; program code means for selecting the non-channel-clarity algorithm from a number of non-channel-clarity algorithms; and program code means for randomly selecting the non-channel-clarity algorithm from a number of non-channel-clarity algorithms.
In all of the embodiments of the devices, programmed devices and methods discussed above the non-channel-clarity algorithm may comprise: an algorithm which orders channels within a group by channel number or by channel frequency; a pseudorandom number generation algorithm for randomly ordering the channels within each group; and an algorithm which makes use of a xe2x80x9clast channel used.xe2x80x9d In addition, the range of channel clarity used to group channels is preferably a perceptible range of channel clarity. The devices and programmed devices may comprise a cordless telephone system, base of a cordless telephone system, handset of a cordless telephone system or a part of a cordless device or system.
The present invention and its advantages can be best understood with reference to the drawings, detailed description of the embodiments and claims that follow.